Scheta was one of the Integrity Knight synthesized after winning a Four Empires Unity Tournament. Due to her reluctance to speak and attract attention, she became known as The Silent among the other knights.
After killing another Integrity Knight in a duel with her Divine Object-class weapon, the Black Lily Sword, Scheta was put into hibernation at her own request, until she was awoken in the aftermath of the battle at the Central Cathedral that resulted in Supreme Priest Quinella's and Chief Elder Chudelkin's deaths.
(Source: Sword Art Online Wiki)